Codeset communication format and related methods and structures

ABSTRACT

A codeset is described in a Public Codeset Communication Format (PCCF) as a format block including a plurality of fields having readily decipherable values, such as ASCII character values. One field is a mark/space information field that includes a sequence of mark time indicators and space time indicators for an operational signal of the codeset. A second field is a signal characteristic information field for the operational signal. Signal characteristic information may include carrier on/off information, repeat frame information, toggle control information, and last frame information. The PCCF is a codeset interchange format of general applicability.

RELATED APPLICATION

This application claims the benefit of and is a continuation of U.S.application Ser. No. 14/276,466, filed on May 13, 2014, whichapplication claims the benefit of and is a continuation of U.S.application Ser. No. 12/706,080, filed on Feb. 16, 2010, whichapplication claims the benefit of and is a continuation of U.S.application Ser. No. 11/359,149, filed on Feb. 21, 2006. Theseapplications are incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present invention relates generally to codesets that are used byremote control devices to generate operational signals that controlelectronic consumer devices.

BACKGROUND

Manufacturers of electronic consumer devices, such as televisions, radiotuners, digital video disk players, video cassette recorders, set-topcable television boxes, set-top satellite boxes, etc., typically supplya remote control device along with each electronic consumer device. Theremote control device can control the associated electronic consumerdevice by sending an operational signal to the electronic consumerdevice. The operational signal may, for example, be the envelope of aninfrared signal. The operational signal carries a key code. Each suchkey code corresponds to a function of the selected electronic consumerdevice, such as power on, volume down, play, stop, select, channeladvance, channel back, etc. Thus, an electronic device is controlled bya codeset of key codes.

Codesets can differ from each other not only by the different key codes,but also by the carrier, timing and framing protocols used to output thekey codes as operational signals. In order to avoid the situation wherean operational signal containing a key code operates an electronicdevice that is not selected, manufacturers of electronic consumerdevices may use different codesets for different devices. Although eachmodel of electronic consumer device might not have a unique codeset,there are nevertheless thousands of codesets used to operate the varioustypes, brands and models of electronic consumer devices sold in theworld market today.

Handheld remote control devices typically include an amount of storage,a processor, and a transmitting device. Where the remote control deviceis a handheld infrared remote control device, the storage is typicallysemiconductor memory that is on the same microcontroller integratedcircuit as the processor. The transmitting device may, for example, bean infrared light emitting diode (LED). Information on one or morecodesets is stored in the memory of the microcontroller. When a key ispressed on the remote control device, the microcontroller accesses thecodeset information and generates an appropriate key code signal. Thekey code signal is modulated with the appropriate carrier and issupplied to the LED, thereby causing the operational signal to betransmitted as an envelope of the infrared signal.

Such microcontrollers are typically supplied to remote controlmanufacturers preloaded with codesets that operate the various types,brands and models of electronic devices that the remote control deviceis to operate. It is therefore of significant value to such amicrocontroller manufacturer to be able to supply the appropriatecodesets needed for each possible remote control application. Amicrocontroller manufacturer that has the codeset needed for aparticular remote control application has a competitive advantage overanother microcontroller manufacturer that does not have the neededcodeset. Some microcontroller manufacturers therefore devote greateffort and expense amassing large and comprehensive databases ofcodesets. These codeset databases are valuable to the microcontrollermanufacturers.

Such microcontroller manufacturers have therefore conventionallyattempted to keep their codeset databases proprietary. When working witha remote control device designer/manufacturer, the microcontrollermanufacturer is careful not to disclose the format of the codesetinformation stored in the microcontroller. The codeset information mayonly be provided to the remote control manufacturer in the form ofinformation stored in a mask-programmable read only memory (ROM) on themicrocontroller integrated circuits. Reading this codeset informationout of the microcontroller may be difficult, thereby helping to keep theinformation confidential. Even if a remote control device manufacturerwere to be able to read the codeset information out of themicrocontroller memory, the remote control device manufacturer would notknow the format of the codeset information. Because a rendering enginein the microcontroller receives information in a particular format andconverts that information into the operational signals, and because howthe rendering engine does this conversion is not known to the remotecontrol device manufacturer, the remote control manufacturer's knowledgeof the codeset information stored in the microcontroller does not allowthe remote control manufacturer to use the codeset information in amicrocontroller from another microcontroller manufacturer. By concealinghow the rendering engine works and the format of information that therendering engine receives as inputs, the deciphering of the codesetinformation stored on the microcontroller is prevented. Conventionally,considerable care is exercised keeping the format of codeset informationas supplied to the rendering engine as much of a secret as is reasonablypossible. Conventionally, the microcontroller manufacturer does notshare the format of the codeset information with any other entity, evenits best remote control device manufacturing customers.

SUMMARY

A codeset is described in a Public Codeset Communication Format (PCCF)as a format block. The PCCF format block includes a plurality of readilydecipherable fields of ASCII character values. Where the various fieldsare in the block and what the various fields contain is made public aspart of the PCCF. One field of the PCCF format block is a mark/spaceinformation field that includes a sequence of mark time indicators andspace time indicators for an operational signal of the codeset. A secondfield is a signal characteristic information field for the operationalsignal. Signal characteristic information may include carrier on/offinformation, repeat frame information, toggle control information, andlast frame information. The PCCF is a codeset interchange format ofgeneral applicability. The PCCF may, for example, be made public byposting it on a publicly available web-site.

In one method, a first entity (for example, a remote control devicedesigner) describes a codeset in the PCCF format and then communicatesthe PCCF format information to a second entity (for example, amicrocontroller manufacturer). The communication can be by any suitablemechanism, but is preferably communication of an ASCII file by reliableelectronic means. The second entity converts the information into aformat usable by a rendering engine. The rendering engine may, forexample, be a part of a microcontroller supplied and/or manufactured bythe second entity. The rendering engine is then usable in the remotecontrol device to generate operational signals of the codeset.

Where the rendering engine is part of a microcontroller supplied by thesecond entity, the second entity may preload the information in theformat usable by the rendering engine into memory in themicrocontroller. The second entity then supplies the microcontrollerpreloaded with the codeset information to the first entity so that thefirst entity can incorporate the microcontroller into the remote controldevice being designed. The remote control device can then use thepreloaded information to generate operational signals in the codeset.

A valuable database of codesets compiled by the second entity (themicrocontroller manufacturer) can also be preloaded into themicrocontroller. Codesets in the database are described in the same PCCFformat as PCCF format blocks. The PCCF format blocks are compressed andreformatted by the second entity into the format that is usable by therendering engine of the microcontroller. The compressed and reformattedinformation is then encrypted by the second entity and is preloaded intothe microcontroller along with the unencrypted codeset informationdescribed above. The microcontroller is then supplied to the firstentity and is incorporated into the remote control device beingdesigned. The encrypted form of the codeset information in themicrocontroller helps maintain the proprietary nature of the codesetdatabase information.

When a key is pressed on the remote control device such that anoperational signal in one of the codesets of the database is to begenerated, the encrypted information is retrieved from microcontrollermemory, is decrypted by the decryptor within the microcontroller, and issupplied in unencrypted form to the rendering engine. The renderingengine uses the unencrypted information to generate the desiredoperational signal for the desired codeset in the database. In this way,a microcontroller can include both encrypted codeset information from acodeset database compiled by the second entity (the microcontrollermanufacturer) as well as unencrypted codeset information that wasoriginally written by the first entity (the remote control devicedesigner) in the PCCF format.

The PCCF format is a codeset interchange format of general applicabilityand can be used to describe and communicate codeset information betweenvarious different types of entities. The interchange is not limited tothe interchanges described microcontroller manufacturers/suppliers andremote control device designers/manufacturers. Accordingly, otherembodiments involving other uses of PCCF format blocks are described inthe detailed description below.

This summary does not purport to define the invention. The invention isdefined by the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, where like numerals indicate like components,illustrate embodiments of the invention.

FIG. 1 is a simplified diagram that illustrates a novel method involvinga PCCF format block.

FIG. 2 is a simplified diagram of multiple codesets described in PCCFformat blocks.

FIG. 3 is a more detailed diagram of one PCCF format block.

FIG. 4 is a diagram of a remote control device showing the X-Ycoordinate grid that is used to describe the location of keys and textin the key layout table of a PCCF format block.

DETAILED DESCRIPTION

Rather than maintaining the format of information in a codeset databaseproprietary, a novel Public Codeset Communication Format (PCCF) isdisclosed. A first entity (for example, a company that supplies and/ormakes microcontrollers and that has also compiled a codeset database)describes the codesets in its database in accordance with the PCCFformat. (The term database is used here in a general non-technical senseand refers to a group of codesets and possibly related information,where the codesets are stored in association with one another.) A secondentity (for example, a remote control device manufacturer) can alsodescribe codesets in the PCCF format.

A particular codeset is describable in the PCCF format as a readilydecipherable format block of ASCII (American Standard Code forInformation Interchange) character values. The format block has multiplefields. One of the fields is a mark/space information field thatspecifies mark times and space times for generating the operationalsignal. Another of the fields is a signal characteristic informationfield that specifies other information about how to render theoperational signal. The signal characteristic information field mayinclude information such as: carrier information, information on how torepeat the operational signal, toggle control information, and lastframe information. The PCCF format block may also contain other fieldsincluding a key layout table. The key layout table sets forth thephysical location of keys on the remote control device to which thecodeset being described pertains. The key layout table may also setforth text that appears printed on the remote control device. The PCCFformat block may also contain other fields including a key functionidentification table. The key function identification table indicateshow a device that receives a particular operational signal will respondto receiving the operational signal. The layout of the various fields inthe format block as well as the meaning of information in each field ismade public. The information content of the various fields is easilydecipherable because the PCCF format block is a block of ASCII charactervalues.

In one novel method, a first entity (for example, a microcontrollersupplier and/or manufacturer that has compiled a valuable database ofcodesets) wishes to receive royalty income for the licensing of thecodeset database to a second entity (for example, a manufacturer ordesigner of a new remote control device). The microcontroller suppliersupplies the remote control device manufacturer with: 1) an encryptedversion of the codeset database, and 2) a microcontroller that includesa rendering engine, a decryptor, and a memory. If the rendering enginereceives codeset information in a particular format, then the renderingengine can generate operational signals in the codeset. The format ofthe codeset information received by the rendering engine is proprietaryto the microcontroller supplier.

All the codesets in the codeset database are described in accordancewith the PCCF format. The information in the resulting PCCF formatblocks is then compressed and reformatted as necessary to put theinformation into a form required by the rendering engine on themicrocontroller. The compressed and reformatted information is thenencrypted and stored in encrypted form in the memory in themicrocontroller. The memory may, for example, be mask programmableread-only-memory (ROM) such that the storing actually occurs at the timeof microcontroller integrated circuit manufacture.

After microcontroller manufacture, the microcontroller can beincorporated into the new remote control device. If a key were pressedon the new remote control device such that an operational signal fromone of the codesets in the data were to be generated by the remotecontrol device, then the appropriate encrypted information in memorywould be retrieved, would be decrypted by the decryptor on themicrocontroller, and would be supplied to the rendering engine. Therendering engine would output an appropriate operational signal thatwould drive a transmitting device (for example, an infrared lightemitting diode) on the remote control device. The resulting infraredsignal would be transmitted from the remote control device and wouldcarry the operational signal to the consumer device to be controlled.If, for example, the operational signal is the operational signal forthe power on command in the proper codeset understood by the receivingelectronic consumer device, then the electronic consumer device powerson as desired.

In the present example, the remote control device manufacturer (thesecond entity) wants the new remote control device to be able togenerate operational signals in a special codeset that is not present inthe codeset database of the microcontroller manufacturer. The remotecontrol device manufacturer, however, is aware of the Public CodesetCommunication Format (PCCF). The remote control device manufacturerdescribes the special codeset in accordance with the PCCF. The resultingPCCF format block is then communicated from the remote control devicemanufacturer (the second entity) to the microcontroller supplier (thefirst entity). The microcontroller supplier compresses and reformats theinformation in the PCCF format block as required to put the informationinto a form that can be understood by the rendering engine on themicrocontroller. If the rendering engine on the microcontroller were toreceive the compressed and reformatted information, then the renderingengine would be able to generate operational signals in the specialcodeset. Accordingly, the microcontroller supplier (the first entity)stores in microcontroller memory both the compressed and reformattedPCCF information for the special codeset as well as the compressed,reformatted and encrypted information from the microcontrollersupplier's codeset database. As a result, when the microcontroller isused in the new remote control device, the new remote control devicewill be able to generate operational signals in the special codeset andwell as operational signals in any codeset in the database.

Because the microcontroller is designed to make the intercepting ofinformation between the output of the decryptor and the rendering enginedifficult, the remote control device manufacturer will not be able toreadily decipher the content of the unencrypted codeset databaseinformation as it passes from the output of the decryptor to therendering engine. The proprietary content of the codeset database istherefore not compromised. Due to the encryption, the codeset databaseinformation as supplied by the microcontroller manufacturer is onlyusable on microcontrollers supplied by the microcontroller supplier (thefirst entity) that have the proper decryptor. The supplier's incomestream from the sale of microcontrollers and from the licensing of thecodeset database is therefore protected. The description of codesets inthe same PCCF format regardless of whether the descriptions weregenerated by the microcontroller supplier (the first entity) or weregenerated by the remote control device manufacturer (the second entity)simplifies the compressing and formatting operations that themicrocontroller supplier has to do to put the PCCF format blocksgenerated by the second entity in a proper form for being used by therendering engine.

FIG. 1 is a simplified diagram that corresponds to the novel method setforth above. Block 1 represents the database of codesets that werecompiled by the microcontroller supplier (the first entity). Thecodesets are described in the PCCF format as a plurality of PCCF formatblocks.

Block 2 represents the PCCF format block that describes the specialcodeset. The PCCF format block was generated by the remote controldevice manufacturer or designer (the second entity).

Blocks 3 and 4 represent the compression and reformatting performed bythe microcontroller manufacturer to convert the PCCF format blocks intoa format that can be received and used by the rendering engine of themicrocontroller. The rendering engine is represented by block 5. Dashedblock 6 represents an operational signal rendering device such as, forexample, a microcontroller.

Block 7 represents the new remote control device that is being designedand/or manufactured by the remote control device manufacturer (thesecond entity). The remote control device 7 can be a handheld infraredremote control device of the form typically used to control electronicconsumer devices such as televisions in the home. The remote controldevice 7 can alternatively be another type of remote control device suchas a personal computer that has a television tuner expansion cardinstalled. Codeset information is stored in the personal computer inmass storage on hard disc or elsewhere. A processor (for example, amicrocontroller supplied by the first entity) on the expansion card usesthis information to generate operational signals. The operationalsignals are supplied to a transmitter (for example, an IR LED) that iscoupled to the expansion card. A signal (for example, an infraredsignal) that carries an operational signal is transmitted from thetransmitter and to an electronic consumer device so that the personalcomputer can control the electronic consumer device. The handheld remotecontrol device and the personal computer having the expansion card arebut two examples of remote control devices. The remote control device 7can take other forms as well.

As described above, the compressed and reformatted codeset informationfrom block 3 is encrypted before it is loaded into the operationalsignal rendering device 6. Block 8 represents this encryption. Theencryption is performed by the microcontroller supplier. The operationalsignal rendering device (in this case, a microcontroller) includes adecryptor 9 for decrypting the information encrypted by block 8. Theoutput of the decryptor 9 is in the compressed and reformatted formrequired by the rendering device 5. Accordingly, the rendering engine 5of FIG. 1 can receive properly compressed and formatted codesetinformation from the first entity's codeset database or from the secondentity's special codeset. The supplying of these two sources ofcompressed and properly formatted information are represented by arrows10 and 11.

The operational signal rendering device 6, in response to receiving keypress information, uses codeset information received via source 10 orsource 11 to generate an operational signal in an appropriate codeset.Where the remote control device is a handheld remote control device of atypical form, the microcontroller has key scanning functionality thatdetects when a key is pressed and reports which key it was that waspressed. Block 12 represents this key press information that causes therendering engine to output an operational signal.

Block 13 represents the transmitting device that communicates theoperational signal. In the present example, the transmitting device isan infrared LED. Block 14 represents the electronic consumer device thatreceives the infrared signal and responds to the operational signal.

FIG. 2 is a simplified diagram that shows the PCCF format block 2generated by the remote control device manufacturer (the second entity)as well as the PCCF format blocks 1 of the codeset database of themicrocontroller supplier (the first entity). The PCCF format block 2 forthe special codeset includes a first portion 15 of type 1 as well as asecond portion 16 of type 2.

FIG. 3 is a more detailed diagram of the PCCF format block 2 of FIG. 2.First portion 15 includes general information that pertains to alloperational signals of the codeset. In first portion 15, the firstasterisk-delimited ASCII field 17 is a title field that contains thevalue “RCA VCR-DVD COMBO”. This value indicates the type of device to becontrolled by the codeset. There may be multiple different codesets thatcontrol the device. For example, a first codeset may be used to controlthe RCA VCR-DVD COMBO device when the device is operating as a VCRwhereas a second codeset may be used to control the device when thedevice is operating as a DVD. In the present example, there is only onecodeset that is used to control the RCA VCR-DVD COMBO device, regardlessof whether the device is operating as a VCR or a DVD.

The second asterisk-delimited ASCII field 18 is a field that containsthe value “D1=DEVICE_VCR”. There may be multiple different models of the“RCA VCR-DVD COMBO” device type. Each such different model would bedesignated with a different device number. The “D1” in the example ofFIG. 3 denotes the first such device. The value “DEVICE_VCR” is anindicator of the first device. In the example of FIG. 3, there is onlyone device of the type “RCA VCR-DVD COMBO”.

The third asterisk-delimited ASCII field 19 is a field 19 called the“key layout table”. The key layout table includes a set ofsemicolon-delimited subfields. The first subfield is “1,0,SAT,;.” Thissubfield includes a set of comma separated subsubfields. The “1” in thefirst subsubfield denotes the X coordinate location of a key on theremote control device. The “0” in the second subsubfield denotes the Ycoordinate location of the key. FIG. 4 is a diagram of the remotecontrol device. The key referred to is the key bearing the text “SAT”.It is located at X-Y location “1,0”. The next subsubfield contains thevalue “SAT”. This value is the text that appears on the key. The lastsubsubfield is blank. This subsubfield could contain a value where thevalue is text that is printed on the remote control device body inassociation with the key. The value being blank indicates that there isno text printed on the remote control device body that corresponds tothe key.

The second semicolon-delimited subfield is “11,0,S,S-POWER.” The “11,0”denotes the X-Y location of the next key. The next “S” indicates that asymbol is printed on the key (rather than text). The next “N-POWER”denotes that the text “POWER” is printed on the body of the remote atlocation to the “north” (above) the key. If the text had appeared belowthe key, then the subsubfield would have the value “S-POWER”, where the“S-” denotes “south”. In the same way, other possible prefixes for thevalue include “E-” and “W-” for “east” and “west”.

The fourth asterisk-delimited ASCII field is a field 20 called the “keyfunction identification table”. The key function identification tableincludes a set of semicolon delimited subfields. The first subfield is“KEY_POWER=VCR_PW_Poweron/Poweroff”. The subfield indicates that the“KEY_POWER” function has the value “VCR_PW_Poweron/Poweroff.” This valueindicates that on each subsequent press of the power key, the VCR poweris turned on, then off, then on, as so forth. The “KEY_POWER” functioncould alternatively have been assigned the value “VCR_PW_Poweron”. Thisvalue would have meant that pressing the power key would turn the VCRpower on. If the VCR power had already been on at the time of the keypress, then the VCR power would have remained on.

The second semicolon-delimited subfield is“KEY_PLAY=VCR_PLAY_Play/Pause”. The “VCR_PLAY_Play/Pause” value meansthat successive pressings of the “PLAY” key cause the VCR to play, topause, to play, to pause, and so forth. The “KEY_PLAY” function couldalternatively have been assigned the value “VCR_PLAY_Play”. This valuewould mean that pressing the play key would cause the VCR to play. Ifthe VCR was already playing, then the VCR would continue playing.

The third and fourth semicolon-delimited subfields are interpreted in asimilar manner. Functions of the form “KEY_XXX” denote what function orfunctions is or are to be performed when the key “XXX” is pressed. Aseries of functions can be specified to be performed in association witha single key. In one example, the value assigned indicates a functionand also indicates that the function is only to be performed if anotherkey is pressed. For example, pressing the “SOURCE” key may change thedesignated source of input for the receiving device from one source toanother, but the actual change of the source will only take place if the“OK” key is pressed next. This is sometimes called an “activate”feature. The activate feature may be indicated by following the firstfunction value with “−A(OK)”. This attribute indicates that the priorfunction is activated by pressing the “OK” key.

In the example of FIG. 3, there are only four asterisk-delimited fieldsin the first portion 15 of the PCCF format block 2. The second portion16 of PCCF format block 2 contains a set of asterisk-delimited fields,where there in one such field for each operational signal to begenerated. Two such fields 21 and 22 are illustrated in the example ofFIG. 3. The first field 21 contains values that relate to the generationof a first operational signal that is output when the power key ispressed. The second field 22 contains values that relate to thegeneration of a second operational signal that is output when the exitkey is pressed.

Field 21 includes two semicolon-delimited subfields. The firstsemicolon-delimited subfield “D: 1,C:0000,K:KEY_POWER” is a subfieldthat contains multiple comma-delimited subsubfields. The firstsubsubfield contains “D:1”. This indicates that field 21 is for device“D1”. As defined above in field 18, device D1 is “DEVICE_VCR”. Thesecond subsubfield contains “C:0000”. This indicates that field 21 isfor codeset number “0000”. The third subsubfield is a key identificationsubsubfield of value “K:KEY_POWER”. This subsubfield indicates thatfield 21 is for the function “KEY_POWER”. The “KEY_POWER” function, asset forth above, defines what happens when the key “POWER” is pressed.

The second semicolon-delimited subfield includes numerous commadelimited subsubfields. A first set of the subsubfields is a “signalcharacteristic information” set of subsubfields. (This “set” ofsubsubfields is also referred to using the general term “field” in thispatent document in order to simplify claim terminology. Accordingly, onefield may be contained in another field. Not all fields are asteriskdelimited.)

The “signal characteristic information” in the example is “9,9,RF,IR”.The “9,9” denotes the carrier on time, and carrier off time,respectively. During a mark portion of an operational signal, theoperational signal is not actually at a digital high for the entireduration of the mark portion, but rather is modulated on and off rapidlyat what is called the “carrier” frequency. The first “9” designates thenumber of time units that the carrier is high during one cycle of thecarrier. The second “9” designates the number of time units that thecarrier is low during one cycle of the carrier. Accordingly, “9,9”designates a 50/50 duty cycle carrier having a total period of 18 timeunits.

The “RF” indicates that the operational signal is a “repeat frame”. Theterm “repeat frame” means that a frame as defined by the followingmark/space values is repeated multiple times. There are different typesof repeat frames. One type of repeat frame is an “infinite repeatframe”. The term infinite repeat means that the frame is repeated overand over as long as the key is held pressed down by the user of theremote control device. Another type of repeat frame is a repeat framethat only repeats a specified number of times. If, for example, theoperational signal that corresponds to field 21 were a repeat frame thatwas to repeat twice, then the “RF” designating “repeat frame” would befollowed by a comma-delimited “2R”. The “2R” would designate that therepeat frame was to be repeated twice regardless of how long the key ispressed. If the frame is only to appear once in the operational signal,then the frame is termed a non-repeat frame. A non-repeat frame isdesignated with the comma-delimited value “NR”. In the example ofoperational signal of field 21, the frame is an infinite repeat frame.This is designated by the “IR” that follows the “RF” designator.

The next comma-delimited values of the semicolon-delimited subfield aremark/space information values. The various mark/space values arecomma-delimited. (These mark/space information values are referred totogether using the general term “field” in this patent document in orderto simply claim terminology. Accordingly, one field may be contained inanother field. Not all fields are asterisk delimited.)

The first “M4000” indicates a mark of a duration of 4000 time units. Thesecond “S4000” indicates a space of a duration of 4000 time units. Whenthe key “POWER” is pressed, the operational signal includes a frame thathas a series of mark and space times that correspond to the string ofmark and space values in the mark/space information.

In the example of the operational signal to be output when the “POWER”key is pressed, all the frames of the operational signal are to be thesame. In some operational signals, however, there may be one or more“last” frames that are different than preceding frames. A last frame isdenoted by a separate semicolon-delimited subfield. The separatesemicolon-delimited subfield starts with carrier on/off information andends with mark/space information. The fact that the subfield describes alast frame is designated by a “LF” in the “signal characteristicinformation” subsubfields that define the frame. If, for example, thelast frame is to be repeated twice, then the “signal characteristicinformation” may be “5,5,RF,2R,LF”. The “5,5” designate the carrieron/off timing. The “LF” indicates that the frame is a last frame. The“RF” indicates that the frame is a repeat frame. The “2 W” indicatesthat the last frame is to be repeated twice. Accordingly, multiple suchsemicolon-delimited frame descriptions can be chained together todescribe an operational signal.

Although not illustrated in the figures, the signal characteristicinformation can include a toggle control subsubfield, and thisinformation can reference descriptions of toggle frames. In one example,“T0,XY” and “T1,XY” are two labels that are usable to delimit toggleframes. The first time the associated key is pressed, a first framewhose description follows the first “T0,XY” label and precedes thesecond “T1,XY” label is transmitted. The next time the key is pressed,the frame whose description follows the second “T1,XY” label istransmitted. The descriptions of each of the two frames is in accordancewith the manner of describing a frame as described above. The value “X”is an ASCII character value that indicates the number of different typesof toggle frames there are. The “X” is a binary exponent such that a “X”value of one indicates two toggle frames. The first toggle frame isdenoted by label “T0”. The second toggle frame is denoted by label “T1”.The value “Y” is a one ASCII character value that can have specialpredefined meanings that describe different toggle frame types. In thepresent ordinary case where each time the key is pressed the type offrame transmitted is alternated between two different types of frames,the “Y” bit is zero.

In the example of FIG. 1, the designer of the remote control device (thesecond entity) describes the new codeset in the PCCF format as theformat block of FIG. 3. This format block is then communicated (forexample, as an ASCII text file) to the microcontroller supplier (thefirst entity). The first entity then compresses and reformats thecodeset information as represented by block 4 in FIG. 1. One way thatthis compression and reformatting can be done is set forth below.

When a key is pressed on the remote control device, the microcontrollerdetermines what action to take. This typically involves identifying theappropriate signal characteristic information and mark/space informationfor the operational signal to be generated. The signal characteristicinformation and mark/space information is stored at a location inmemory. The microcontroller uses the information in the first set ofsubfields to generate a pointer to the appropriate information inmemory. If, for example, the remote control device were in the “VCR”mode where the remote control device is to control the “DEVICE_VCR”, andcodeset “0000” is to be used, and the “POWER” key was pressed, then thisinformation would be used to point to a location in memory where thesignal characteristic information and mark/space information for field21 is stored. Accordingly, the compression and reformatting operationpacks the various pairs of signal characteristic and mark/spaceinformation fields together in memory and builds a corresponding amountof pointer information that allows the microcontroller to generate anoffset pointer to the appropriate place in memory depending on the keythat was pressed and the mode in which the remote control device isoperating.

Although the signal characteristic information values appear in PCCFformat block 2 as ASCII character values so that they will be readilyreadable by a human, the various values of the signal characteristicinformation do not actually need eight bits or more to convey the neededinformation. For example, the subsubfield that designates whether theframe is a repeat frame or a non-repeat frame can only have one of twovalues. The “RF” value corresponds to one value. The “NR” valuecorresponds to the other value. When the PCCF format block 2 iscompressed and reformatted by block 4, the value of this subsubfield isconverted into a single-bit value. In a similar way, the various othersubsubfields of the signal characteristic information are representableby smaller numbers of bits than the ASCII character values consume inthe PCCF format block. There is a one-to-one correspondence between thevarious ASCII subsubfields in the PCCF format block and the smallersubsubfields in the compressed and reformatted information. Therendering engine 5 includes a parser that knows where the varioussmaller subsubfields are located in the compressed and reformattedinformation.

Block 4 also compresses and reformats the mark/space information. Ratherthan representing each mark space by multiple human-readable ASCIIcharacters such as “M4000”, the same information is representable by atable that contains the mark time of 4000 units, and a pointer thatpoints to the 4000 units entry in the table. Block 4 creates a tablecontaining one entry for each different mark and space time value, andthen replaces the mark/space time values in the description of theoperational signal with a string of short pointers to entries in thetable where the actual mark and space times can be found. Because thereis a relatively small number of entries in the table, the pointers tothe table entries can have a relatively small number of bits. Therendering engine 5 knows where the table is found in memory, and usesthe pointer values to obtain the actual mark and space times in order togenerate the operational signal.

Although a method is described above that involves describing codesetsof a codeset database in the PCCF format, and then compressing,reformatting and encrypting the information before it is communicatedfrom the entity that compiled the codeset database (the first entity) toanother entity (the second entity), the PCCF format can be used inanother method to communicate PCCF format blocks in the decipherableASCII form from the first entity to the second entity in uncompressed,unreformatted, and unencrypted form. PCCF format blocks may, forexample, be communicated from one entity to another under license toprotect the proprietary nature of the codeset information contained inthe PCCF format blocks. The PCCF format is a codeset interchange formatof general utility.

Where the remote control device is a personal computer or other devicethat has a relatively large amount of memory storage space available tohold the codeset database information, storing the codeset databaseinformation in the larger PCCF format blocks may be preferable tostoring the information in a compressed and reformatted format that isnot so readily read by a human. The personal computer can be programmedto receive the PCCF format blocks in ASCII form, to parse the PCCFformat blocks to extract the various values as explained above, and togenerate operational signals that are used to drive a transmitter (forexample, an IR LED) coupled to the personal computer. Alternatively, amicrocontroller having the rendering engine described above is providedby the first entity for incorporation onto an expansion card that is inturn incorporated into the personal computer remote control device beingdesigned by the second entity. Software that executes on the personalcomputer is written to perform the necessary compression andreformatting needed to convert the PCCF format block ASCII informationinto a form that can be received and understood by the rendering enginein the microcontroller. PCCF format blocks in ASCII form are read out ofmemory in the personal computer, are compressed and reformatted, and aresupplied to the microcontroller such that the microcontroller outputsoperational signals. The operational signals are supplied to atransmitter (for example, an IR LED) to communicate the operationalsignals to an electronic consumer device to be controlled.

Although the present invention has been described in connection withcertain specific embodiments for instructional purposes, the presentinvention is not limited thereto. A file of PCCF format blocks caninclude a machine-readable PCCF version number field that indicates theversion of the PCCF format that is used in the file. The PCCF formatfield allows the PCCF format to be revised and added to over time in anupward compatible way. The file of PCCF format blocks can includehuman-readable text information fields at various places in the filethat set forth the various fields of the PCCF format, how they can bedelimited, and what kind of information each of the fields can contain.A person who has such a file can use the embedded text informationfields to determine how a particular codeset can be described in a waythat is consistent with the PCCF format of the file. The various fieldsin the PCCF format block can be delimited with any particular ASCIIcharacter or group of ASCII characters. The delimiter examples set forthabove involving asterisks, semicolons, and commas are just examples.Although the codeset communication format is explained above to bepublic, the codeset communication format may be supplied to selectedentities pursuant to an agreement that the recipient use the knowledgeof the format in a particular way only. The codeset communication formatmay, in such an example, see limited and controlled distribution and inthis sense is not public. The description of codesets in text in thePCCF format is not, however, an incidental occurrence, but rather is tobe more widely practiced as a way for codeset information to becommunicated between an entity that maintains a codeset database (forexample, a microcontroller supplier) and other entities (for example,remote control device designers) that license use of the codesetdatabase or parts of the codeset database. Accordingly, variousmodifications, adaptations, and combinations of various features of thedescribed embodiments can be practiced without departing from the scopeof the invention as set forth in the claims.

What is claimed is:
 1. A method comprising: describing a codeset in aformat block comprising a first portion and a second portion, whereinthe first portion has a first data field that describes a key of acontrolling device and a second data field that describes at least onefunction that is to be performed by a controllable device in response toan activation of the key, wherein the key of the controlling device andthe at least one function that is to be performed by the controllabledevice are each described via use of one or more characters taken froman alphabet, wherein the one or more characters taken from the alphabetfor use in describing the key of the controlling device are visiblyreproduced on the controlling device in association with the key of thecontrolling device, and wherein the second portion comprises informationthat is to be used by a processing device of the controlling device inresponse to an activation of the key of the controlling device to causea transmission device of the controlling device to transmit to thecontrollable device at least one command communication for controllingthe at least one function of the controllable device that is describedwithin the second data field; providing the format block to thecontrolling device; and causing the controlling device to use the formatblock to configure itself to issue command communications to thecontrollable device in response to an activation of the key of thecontrolling device.
 2. The method as recited in claim 1, wherein thefirst portion further includes a third data field that describes a typefor the controllable device via use of one or more characters selectedfrom the alphabet.
 3. The method as recited in claim 2, wherein thefirst portion further includes a fourth data field that describes abrand for the controllable device via use of one or more charactersselected from the alphabet.
 4. The method as recited in claim 1, whereinthe controlling device uses the information in the second portion of theformat block to generate a pointer to command generating informationstored within a memory of the controlling device.